﻿//
// (C) Copyright 2009 Irantha Suwandarathna (iranthas@hotmail.com)
// All rights reserved.
//

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using EffiProz.Core.Lib;
using EffiProz.Core.DataTypes;
using EffiProz.Core.Indexes;
using EffiProz.Core.Errors;
using EffiProz.Core.Persist;
using EffiProz.Core.Results;

namespace EffiProz.Core
{
    public class StatementExpression : StatementDMQL
    {
        public Expression expression;

        /**
         * for RETURN and flow control
         */
        public StatementExpression(Session session, ParserDML.CompileContext compileContext,
                            int type, Expression expression)
            : base(type, StatementTypes.X_SQL_CONTROL, null)
        {

            _isTransactionStatement = false;
            this.expression = expression;

            setDatabseObjects(compileContext);
            checkAccessRights(session);
        }

        public override String getSQL()
        {

            StringBuilder sb = new StringBuilder();

            switch (type)
            {

                case StatementTypes.RETURN:
                    /*
                                    sb.Append(Tokens.T_RETURN);

                                    if (expression != null) {
                                        sb.Append(' ').Append(expression.getSQL());
                                    }
                                    break;
                    */
                    return sql;

                case StatementTypes.CONDITION:
                    sb.Append(expression.getSQL());
                    break;
            }

            return sb.ToString();
        }

        protected String describe(Session session, int blanks)
        {

            StringBuilder sb = new StringBuilder();

            sb.Append('\n');

            for (int i = 0; i < blanks; i++)
            {
                sb.Append(' ');
            }

            sb.Append(Tokens.T_STATEMENT);

            return sb.ToString();
        }

        public override Result execute(Session session)
        {

            Result result;

            try
            {
                result = getResult(session);
            }
            catch (Exception t)
            {
                result = Result.newErrorResult(t, null);
            }

            if (result.isError())
            {
                result.getException().setStatementType(group, type);
            }

            return result;
        }

        public override Result getResult(Session session)
        {

            switch (type)
            {

                case StatementTypes.RETURN:
                case StatementTypes.CONDITION:
                    return this.getResultValue(session);

                default:
                    throw Error.runtimeError(ErrorCode.U_S0500, "");
            }
        }

        public override void resolve()
        {

            bool resolved = false;

            switch (type)
            {

                case StatementTypes.RETURN:
                    if (root.isProcedure())
                    {
                        throw Error.error(ErrorCode.X_42602);
                    }

                    resolved = true;
                    break;

                case StatementTypes.CONDITION:
                    resolved = true;
                    break;

                default:
                    throw Error.runtimeError(ErrorCode.U_S0500, "");
            }

            if (!resolved)
            {
                throw Error.error(ErrorCode.X_42602);
            }
        }

        public override String describe(Session session)
        {
            return "";
        }

        private Result getResultValue(Session session)
        {

            try
            {
                Object value = null;

                if (expression != null)
                {
                    value = expression.getValue(session);
                }

                return Result.newPSMResult(type, null, value);
            }
            catch (CoreException e)
            {
                return Result.newErrorResult(e);
            }
        }

         public  override void collectTableNamesForRead(OrderedHashSet set) { }
       
    }
    
}
